package com.linkai.JUC._02_pc;

/**
 * @Description: 生产者消费者问题：使用 synchronize
 *                线程之间的通信过程：生产者消费者问题  等待唤醒，通知唤醒
 *                线程交替执行 A B 操作同一个变量 num = 0
 * @Author: 林凯
 * @Date: 2021/10/23 19:20
 */
public class _01_ProducerSynchronize {
    public static void main(String[] args) {
        DataSynchronize dataSynchronize = new DataSynchronize();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    dataSynchronize.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "A").start();

        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    dataSynchronize.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "B").start();

        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    dataSynchronize.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "C").start();

        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    dataSynchronize.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "D").start();

    }
}

// 资源类; 单独的资源类，降低耦合性
// 判断等待，业务，通知
class DataSynchronize {
    private int number = 0;

    // +1
    public synchronized void increment() throws InterruptedException {
        // 防止“虚假等待”，这里需要使用 while
        while (number != 0) {
            // 等待
            this.wait();
        }
        number++;
        System.out.println(Thread.currentThread().getName() + number);
        // 通知其他线程，我+1完了
        this.notifyAll();
    }

    // -1
    public synchronized void decrement() throws InterruptedException {
        while (number == 0) {
            // 等待
            this.wait();
        }
        number--;
        System.out.println(Thread.currentThread().getName() + number);
        // 通知其他线程，我-1完了
        this.notifyAll();
    }
}
